Various products which incorporate or utilize single phase or three phase induction motors can benefit from the use of an electronic motor starter. For example, an electronic motor starter can provide many advantageous features, including: controlled in-rush currents, smoother starting torque profiles, and system fault detection. However, due to the high cost of electronic motor starters relative to electromechanical starters, products which include or utilize motors often rely on electromechanical starters.
Generally, a significant portion of the cost of an electronic motor starter is related to the heat dissipation requirements associated with the power semiconductor devices which control the amount of current provided to the motor. These heat dissipation requirements typically command that large heat sinks be attached to the power semiconductor devices of the electronic motor starter. These large heat sinks are required to provide a method of removing the large amount of heat energy produced in the power semiconductor devices that control the motor's operation. The quantity of the materials used and the manufacturing processes performed to create these heat sinks add greatly to the cost of the electronic starter. The large heat sinks are also primarily responsible for the overall size and weight of the electronic starter.
Additionally, the higher cost of the electronic motor starters is somewhat related to the current capability and packaging of the power semiconductor device. For electronic starters, choosing power semiconductor devices that can handle the thermal issues associated with the continuous operation of the motor add additional expense to the starter.
Further, electronic motor starters require a power supply to power the operation of the electronics controlling the firing of the motor. A user interface is often included with electronic motor starters which allows the user to set particular starting and running characteristics for the motor. The power supply and user interface can add additional expense to the electronic motor starter.
Thus, there is a need for an electronic motor starter which can be utilized in motor control applications typically handled by less expensive electromechanical motor starters. Further, there is a need for a low-cost electronic motor starter which can be retrofitted to replace existing electromechanical motor starters. Further still, there is a need for an electronic motor starter which can be utilized in cost-sensitive motor control applications and yet provide the advantages associated with an electronic motor starter, such as, reduced in-rush currents, smoother starting torque profiles, and system fault detection. Even further still, there is a need for an electronic motor starter optimized to reduce heat dissipation requirements.